For emails or general web pages, one way is to highlight the area of print you want printed, Right click on the highlighted area, or go to menu bar at top and select “File”, then click on “Print preview”. You can also just right click on the page and choose Print Preview, or go to your menu bar at the top of your web browser, click on "File" then "Print Preview”, without highlighting everything.
Find the drop down box "As laid out on screen" and change to "As selected on screen", this should make a big difference as to what you see will be printed out, but if you still need to change it further, then change the “Shrink to fit” setting to change it to increase or reduce the image size that you want to use, something like 90% (there is a custom option at the bottom of the list if you need to set something unique in between what's listed) and see how it changes the print size of what is to be printed out and choose a percentage that looks and works best for you without cutting off text/image somewhere. This will make it larger or smaller when printed out as seen on the preview print window depending on what you choose.
Another way that usually works to make the print larger when printing internet stuff & emails is by changing the view size on the screen to a larger size in your web browser (this is separate from your other setting you've already setup). Go to the menu bar at the top (i.e. Internet Explorer), click on "View," then "Text Size" then select a size like "Larger" or "Largest" (something higher than what you're currently set to.)
Sometimes adjusting the current window's magnification (lower right corner of screen or Ctrl button + scroll wheel on mouse) can have an affect on print size.
The only other method is to copy & paste the text into a text editing software like Word and adjust the text size there. If you're using a text program, then you simply adjust the size of the text to a 12 or 14 point, or larger, font size (adjust depending on the font and size you need) and that should do the trick.